Proximate Composition of Dioscorea dumetorum (K.) and Dioscorea bulbifera (L.) Tubers during Storage

Abstract

Yam is a staple food of sub-saharan African, consumers have consistently doubted, the actual nutritional compositions of the tubers during storage. There has been continued need to understand the composition of yam tubers at various stages of storage, especially after sprouting. This research determined the proximate composition of Dioscorea dumetorum and Dioscorea bulbifera during storage. The proximate analysis involved the moisture content, crude protein, fat, carbohydrate, crude fiber and dry matter of the two yam species at storage. Sample obtained from two species were subjected to proximate assay. Analytical methods were used for the nutritional assay. Data from analysis were subjected to ANOVA and means separated using DUNCAN'S Multiple Range Test. Test of significance was based on 5% probability level. Proximate analysis of Dioscorea dumetorum revealed that, the tail region of immediately after harvest gave the highest protein content (78.68±0.28) which was significantly higher than that of the tail region of post sprouted stage (77.98±0.18).Carbohydrate content Dioscorea dumetorum was highest in the head region of second stage (98.39±0.11) while the least was in the head region of third stage (77.78±0.19) and the Dioscorea bulbifera, the head regions of all the storage gave the significantly highest carbohydrate composition value, the tail region showed the lowest or no significant across the column. This study revealed that there is a mobilization and utilization of proximate of tubers of two yam species during storage.